Solar oxidation of toluene over Co doped nano-catalyst

Cobalt (Co) co-doped TiO2 photo-catalysis were synthesized, characterized and tested toward solar photocatalytic oxidation of toluene (TOL). A multi-technique approach was used to characterize and relate the photo-catalytic property to photo-oxidation performance. Adding Co to TiO2 significantly changed crystal size and surface morphology (surface area, pore-volume, and pore size), reduced the bandgap energy of TiO2 and improved the solar photo-oxidation of TOL. Up to 96.5% of TOL conversion (% TN..) was achieved by using Co TiO2 compared with 28.5% with naked TiO2. The maximum %Thiconv was achieved at high hydraulic retention time (HRT) >= 100 s, Co content in the photo-catalyst of 5 wt% and relative humidity (%RH) of 50%. The mechanism of TOL solar oxidation was related to the concentration of OH center dot and center dot O-2(-.) radicals produced from the generated electrons and holes on the surface of Co TiO2. The products formed during the photo-catalytic oxidation of TOL were mainly CO2 and water, and minor concentration of benzene and benzaldehyde. Overall, the Co-TiO2 could be used as a potential photo-catalyst for the oxidation of toluene in gas-phase streams on an industrial scale. (C) 2020 Elsevier Ltd. All rights reserved.